ClearRTOS示例代码

/****************************************************************************** * * * This program is distributed in the hope that it will be useful, but * * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * * or FITNESS FOR A PARTICULAR PURPOSE. This file and program are licensed * * under the GNU Lesser General Public License Version 3, 29 June 2007. * * The complete license can be accessed from the following location: * * http://opensource.org/licenses/lgpl-3.0.html * * * * Author: Yun Li (yunli.open@gmail.com) * * Date: 05/22/2010 * * * ******************************************************************************/ /****************************************************************************** REVISION HISTORY ================ Date Version Name Description ---------- ------- ------------ ------------------------------------------- ---------- ------- ------------ ------------------------------------------- ******************************************************************************/ //lint -esym(728, g_scheduler_locked_count, g_statistics) #include "console.h" #include "clib.h" #include "task.h" #include "idle.h" #include "errtask.h" #include "clock.h" #include "hook.h" #define TASK_PRIORITY_LEVELS BITS_SUPPORTED #define TASK_LAST_INDEX (TASK_PRIORITY_LEVELS - 1) #define TASK_PRIORITY_LOWEST TASK_LAST_INDEX #define IDLE_TASK_PRIORITY TASK_PRIORITY_LOWEST #define MAGIC_NUMBER_TASK 0x5441534BL // keep this in line with stack_unit_t #define STACK_WIDTH_IN_BYTES 4 #define STACK_WIDTH_SHIFT4BYTE 2 #define MAGIC_NUMBER_STACK 0xDEAD5AA5L #define is_invalid_handle(_handle) (((_handle) == null) || \ ((_handle)->magic_number_ != MAGIC_NUMBER_TASK)) typedef struct { statistic_t scheduled_; statistic_t overflowed_; statistic_t invalid_handle_; } task_statistic_t; static task_t g_task_pool [TASK_PRIORITY_LEVELS]; task_bitmap_t g_ready_bitmap; static task_handle_t g_priority_map [TASK_PRIORITY_LEVELS]; static device_handle_t g_tick_handle; static int g_scheduler_locked_count; static dll_t g_allocated_task; static task_statistic_t g_statistics; static task_handle_t g_task_running; static task_handle_t g_task_idle; static task_context_t g_start_context; static bool g_multitasking_started; // this is the entry function for all tasks, it calls the entry function setting // by the user via task_start () static void task_main () { task_handle_t handle = g_task_running; global_interrupt_enable (INTERRUPT_ENABLED); // the entry function should not return, otherwise, it means the task is // going to be exited handle->entry_ (handle->name_, handle->argument_); // delete the task if the entry function returns, task_delete () could // return an error code if this is the second time to delete it, so, always // ignore return value (void) task_delete (handle); } static void task_timer_callback (timer_handle_t _handle, void *_arg) { task_handle_t p_task = (task_handle_t)_arg; interrupt_level_t level; UNUSED (_handle); level = global_interrupt_disable (); if (TASK_STATE_WAITING == p_task->state_) { (void) task_state_change (p_task, TASK_STATE_READY); p_task->ecode_ = ERROR_T (ERROR_TASK_WAIT_TIMEOUT); } global_interrupt_enable (level); } error_t task_state_change (task_handle_t _handle, task_state_t _new_state) { error_t ecode = 0; if (_handle->state_ == _new_state) { return 0; } switch (_new_state) { case TASK_STATE_CREATED: { #define TIMER_PREFIX "Task:" char timer_name [NAME_MAX_LENGTH + 1] = TIMER_PREFIX; // initialize the stack with value of MAGIC_NUMBER_STACK stack_unit_t *p_unit = (stack_unit_t *)_handle->stack_base_; int count = _handle->stack_size_ >> STACK_WIDTH_SHIFT4BYTE; while (count > 0) { *p_unit ++ = MAGIC_NUMBER_STACK; count --; } context_init (&_handle->context_, _handle->stack_base_, _handle->stack_size_, (address_t) task_main); strncpy (&timer_name [sizeof (TIMER_PREFIX)], _handle->name_, sizeof (timer_name) - (sizeof (TIMER_PREFIX) + 1)); timer_name [sizeof (timer_name) - 1] = 0; ecode = timer_alloc (&_handle->timer_, timer_name, TIMER_TYPE_INTERRUPT); if (0 != ecode) { return ecode; } } break; case TASK_STATE_READY: { if (TASK_STATE_RUNNING == _handle->state_) { break; } if (timer_is_started (_handle->timer_)) { (void) timer_stop (_handle->timer_, null); } task_bitmap_bit_set (&g_ready_bitmap, _handle->priority_); g_priority_map [_handle->priority_] = _handle; } break; case TASK_STATE_RUNNING: { } break; case TASK_STATE_SUSPENDING: { if (timer_is_started (_handle->timer_)) { (void) timer_stop (_handle->timer_, &_handle->timeout_); } task_bitmap_bit_clear (&g_ready_bitmap, _handle->priority_); } break; case TASK_STATE_WAITING: { if (_handle->timeout_ != 0) { (void) timer_start (_handle->timer_, _handle->timeout_, task_timer_callback, _handle); _handle->timeout_ = 0; } task_bitmap_bit_clear (&g_ready_bitmap, _handle->priority_); } break; case TASK_STATE_DELETED: { task_bitmap_bit_clear (&g_ready_bitmap, _handle->priority_); (void) timer_free (_handle->timer_); } break; } _handle->state_ = _new_state; return 0; } void task_schedule (preschedule_callback_t _callback) { interrupt_level_t level; task_handle_t running, successor; bool overflowed = false; level = global_interrupt_disable (); if (!g_multitasking_started) { global_interrupt_enable (level); return; } if (is_in_interrupt () || g_scheduler_locked_count != 0) { global_interrupt_enable (level); return; } successor = g_priority_map [task_bitmap_lowest_bit_get (&g_ready_bitmap)]; if (successor == g_task_running) { global_interrupt_enable (level); return; } running = g_task_running; g_task_running = successor; if (0 == is_stack_overflowed (running, &overflowed)) { if (overflowed) { console_print ("\n\nError: stack overflow for task \"%s\"\n\n", running->name_); (void) task_suspend (running); g_statistics.overflowed_ ++; } } if (TASK_STATE_RUNNING == running->state_) { (void) task_state_change (running, TASK_STATE_READY); } (void) task_state_change (successor, TASK_STATE_RUNNING); g_statistics.scheduled_ ++; successor->stats_scheduled_ ++; if (null != _callback) { _callback (running, successor); } task_switch_hook_traverse (running, successor); context_switch (&running->context_, &successor->context_); global_interrup